Conventional wafer-based solar cells are relatively large and have a horizontal junction formed along a surface of the wafer. Electrical current generated by the solar cell must be transported to terminals of the solar cell in order to be extracted. Since the conductivity of silicon itself is insufficient to transport this electrical current along large distances, metal fingers are used to conduct the current to the terminal regions. However, there are several disadvantages related to the presence of such metallic fingers, which relate to their cost, shading losses, enhanced recombination at metal/semiconductor interfaces, diffusion of metal particles into active areas of the solar cells, resistive losses within the metal fingers, metal adhesion problems and encapsulation requirements.
The performance of solar cell systems can be improved by scaling down the dimensions of each solar cell of such a system thereby increasing the number of solar cells per unit area.
For example, the so-called “Sliver cell” technology may be used to form a plurality of such small solar cells that are interconnected in series. However, large-scale production at low cost remains a challenge.
The present invention provides further improvement.